The young man seemed to be the perfect recruit for the Afghan National Army. He was smart and motivated and, more important, from a part of the country that had felt alienated from the U.S.-backed regime in Kabul for way too long. So Nangyalai Talash, born and raised in the restive province of Maidan Wardak, was quickly signed up by NATO and the Afghan government in their drive to create a bigger, more self-sustaining and integrated military.

For three years, he proved a good soldier. Talash earned enough trust to be enrolled...